Insulating confined spaces



April 13, 194s.

c. c. HERITAGE INSULATING CONFINED SPACES Filed March 2.1943 2 Sheets-Sheet 2 Patented Apr. 13, 1948 INSULATING CONFINED SPACES Clarkl C. Heritage, Cloquet, Minn., assis-nor `to Wood Conversion Company, St. Paul, corporation of Delaware Minn., a

Application March 2, 1943, Serial No. 477,755V

4 claims. (ci. 2li-101i The present invention relates to the placement of particles of thermal insulating `material to build up a thermally insulating integrated mass of such material in a confined space. In particular it relates to `carrying the material in a gaseous vehiclelhereinafter referredto as air) to a deposited growing mass of such particles formed by tion of particles from the vehicle.

In its general aspect, the invention contemplates completely conning a spaceto be so lled with insulation material, whereby to define the form of the mass to be produced. The space may be provided substantially completely by or within existing articles. However, as required or desired forV the purposes of the invention, the space to be filled is completely defined by bounding facial walls having essentially some ltering area for exhausting the gas in which particles of the insulating material are introduced, and having essentially in the area of the confining wallsV one or moreinlet areas for introducing. the gas containing the particles, each such inlet area being essentially in and a fraction of a confining `wall or face in a manner analogous to the relation of the area of a pouring sprue in molds for casting metal articles to aspace-dening area of the mold. It is also a general aspect of the invention that the particles of insulating material are such as may be consolidated into a gas-filtering body, when in nally deposited form,rwhereby in conducting and completing the introduction, gas entering the space through inlet area may pass through all or a part of the body as required to deposiexhaust through filtering area.

Another general aspect of the invention permits the form of the space to be complex, or angular, and not limited to panel-form spaces. Thus, the vehicular stream of gas is introduced atsa differential pressure, relative to the pressures at inlet area and `at filtering area, and at such a velocity that the particles suspended in the gasV are carried with turbulence inside the space to all portions of the space remote from inlet area, and that the differential pressure packs `the deposited mass toa consolidated body filling the spacewhile said pressure of the gas stream is maintained to and, if desired, even after the complete lling of the space. R

The invention is applicable in many fields, for example in packing ber or other insulating materialiinto carboys .to protect and insulate the flasks of liquid therein. However, its presently preferred use is in insulating the doors and cabinets of refrigerators, such. as are` used in homes. In the iieldA of articial refrigeration, high standards for insulation in domestic and other refrigerators have developed in order to minimizel heat loss, because high heat loss adds to the cost of operation. Gonsiderable difliculty has been encountered in the commercial development of refrigerator insulation in parallel `with the development of domestic artificial refrigeration. Along with vhigh standards and for low heatloss, lowV cost of insulatinggmaterial and of insulating process are important, as are uniformity in each cabinetfand uniformity from cabinet to cabinet in a production'line.

In addition, `there isfthe problem of permanence, in which resistance toi settling of packed bulkinsulation is most important. Such resistance can be attained lbyincreasing the density of packing, with which heat leak or heat conductance increases, as a general rule, in the ranges encountered in refrigerators. Itis, therefore, importantto minimize density, consistently with acceptable resistance to settling and acceptable insulatingvalue. .All these factors lead to a need for a processwhich is subject; to control f or meetingthem.y

In the prior art therehas `been no low-cost process for packing a. specified material uniformly and integrally into a cabinet, and uniformly from cabinet to cabinetin a 'prociuction line. The present invention provides such a process, and so used it gives reproducible results with any reproducible material. Vegetable fibers such as from wood may readily be produced from `time to time with reproducible properties within given specifications, and with such material and with the present invention, a low-cost process `for uniformly and eiciently insulatingspaces, such as those iny refrigerators, becomes available to the manufacturers of Y refrigerators. Reference is made to myy Qopending applicationserial No. 336,-

495,filed May 22, 1940, now Patent No. 2,325,055,

issued July 7, 1943, describing reproducible fibers, which arensefulas particles forpractice of the present invention. y T x l l The present invention isa continuation-impart of my prior, application Serial No. 294,212, led September 9,1939,wherein vthe principles of the process are disclosed, which application is generic tothe present application. Theparent application Serial No. 294,212is generic'to Serial Nos.V

477,751, 477,752 and the.` instant application, all filed March 2,11943, as continuations-in-part of said parent application In the series of applications: Serial Nos'. 294,212, 477,751, 477,752 and thel instant application, Serial No. 477,755, the invention being claimed in each application is to retain the particles and. exhaust the gas. The locationof inlet area, the number of inlet areas, and the location, size and numberv of` filtering tareas are not criticalwith respect to y any given space. This is because the stream of gas is introduced at a velocity `to. impel the particles with turbulence into theh space and to all parts `of the space. The greater the shortest distance from inlet area to filtering area, `the thicker is the body of insulating material through which gasimust pass to exhaust. Therefore, for practical convenience, it isdesirable to have filtering area close to, or even adjacent to inlet area.; Experience has shown that, because of the turbulence, the particles may deposit in regions some of which are adjacent to filtering area, and others of which are remote from both inlet area.,v and filtering area. The resulting deposit grows toward the inlet area, and to or through the inlet area. In such case the filtering area close to or adjacent inlet area facilitates the deposition `of the last-deposited material. The conditions establish a complexity of `air currents which change as the remaining space to be filled changes. Cyclonic currents have been observed which tend to Vthrow carried particles centrifugally out of the local air stream andgdeposit them by centrifugal force and in the manner described. Also direct deposition by filtration has been observed -as one of the resulting actions todeposit the introduced particles.

In my said earlier application Serial No.

294,212, I have disclosed the filling of a refrigerator cabinet in which is `mounted a food com,- partment, by use ,of a fixture closure over a peripheral area at the door-opening of the cabinet, which area communicates with the space to be insulated between the cabinet and the food compartment. Where there are openings ,in the food compartment and the cabinet to accommodatethe insertion intothe food compartment of a refrigerating unit, as disclosed therein, one or both of said openings may be cl-osed, or may have filtering area. i

According to the present invention, one or `both of these openings have filtering area in such practice. The case where such openings, if they exist, are closed is described and claimed generically in my coiiled application Serial No. 477,751, and specifically in my coiiled application Serial No. 477,752, each of which applications is generic to the present application. i

Fig. 1 represents in plan view a conventional refrigerator cabinet Ilying on its back. There is a door opening at the top. The cabinet shell, when of metal, has a peripheral internal :Bange I I, across corners of which braces I2 are secured. A food compartment I3 is mounted inside lthe cabinet by means of an external flange I4 thereon, secured to said braces I 2. This forms a space I5 around the food compartment, and under it `(in the position shown), to receive insulation. In the back of the food compartment is illustrated a wire screen` I6 suitably closing an opening in the food compartment which is provided for use in connection with a` refrigerating unit, said screen servingas a wall to confine said space I5, and providing filtering areain such spaceconiining Wall.

In the finished refrigerator, breaker-strip material, shown in fragmentary form atl II, covers the open space at the door opening, this being suitably secured as to the flanges Il and I4. A cover plate is shown in part at I8, forthe bottom front of`the operating refrigerator, be,-

hind which operating machinery is located. A screened opening I9 (Fig. 1) in the bottom rear of thecabinet space to be insulated may be pres# ent, the hole serving for connections from the operating machinery to the refrigerating unit, and the screen serving as filtering area.

The peripheral open space I5 at the door opening is covered by a temporary closure, or fixture shown in Figs. 2 and 3. The closure comprises a frame of members 20 fitting over flange I4, and a frame of members 2| fitting over ange II with space betweenlthe frames. At the corners, this space may be, and is, covered with means 23 providing imperforate area, also confining said space` I5. Adjacent the corners are screens 24 providing filtering area for confining said space I5. Between the pairs of screens on each panel side of space I5, there is inlet area 25. Directly over the inlet areas 25 there are provid-ed hoods 20 to 29 which are connected lby conduits 30 to a common unit 3| into which the air stream is blown. Hoods 28 and 29 may be bifurcated internally as sho-wn. Windows 32 permit seeing whenfiber or the like packs into the hoods, indieating completionof the filling of space ,I 5, As illustrated in Fig. 4, which is a vdiagrammatic cross-section on line 4-4 `of Fig. 1,` there is an opening in the cabinet IIJ opposite the screen I6, which opening in the cabinet is shown `closed by a plate or other means 35, which may be the surface of a platform on which the back` of the cabinet lies.

Fig. 5 is a modification of the arrangement already described, in form similar to that of Fig. 4, in which a screen 36 .closes the opening in the cabinet, `and a plate 3'I closes the opening in the food compartment I3.

Fig. 6 is a modification of the two above arrangements, inform similar to that of Figs. 4 and 5, in which screens 38 yand 39c1ose` the openings respectively of the cabinet I0 and food cornpartment I3.

. Fig. 7 shows a blower system to which the common unit 3I (Figs, 2 and `3), may be connected. A fan-type blower 45 has pipe 46, for the entry of air, into which fiber may be fed by hand, or by a mechanical device, suchas a picker, or a worm screw 46a. The fan discharges downwardly through conduit 41.

Consider the apparatus of Fig. 7 when the pipe 41 is 6 inches in diameter, and connected to a fixture for filling a space. The fan is operated at 3740 R. P. M. by a 15 H. P.motor of 18,00 R. P. M. Runningidle (connected and operatedbut no fiber fed), the measured pressures :are as follows:

The system shown in Fig. 7 has been used to fill a certain space 1A full, then to l full, then to 3A full, and then to 100% full, with measure ments of the system (idle) at each stage. The measured values are combined in Table II with values taken from Table I and are in the same units as those4 in Table I.

Table-II Measured inpipeh f empty satan. mum mun son Statis pressure 8.5 l2. l2; Y l3.li 114. 75 Total pressure 10. 13y 13 13.5 14.75 kVelocityvpressure `1.75- l i Velocity 53004 4096 Output 1040 '185 It is noted .that .underconditions where the .exit is wholly or to a, degree blocked, as .when Athe space is full, .there isa back pressure encountered at the inlet tothe centrifugal fan.

The `back-.pressure is ,an important feature of the use of super-.atmospheric pressure feed, with apparatus permitting back pressure. Consider in Fig. 1, that the fan may run while ,the feed line 41 is open. A momentum is established into .pipe 4.1. As .this is blocked off, .the moving stream is retarded, at rst in part, .and ber `gradually nlls up the inlet conduits. A window (later described) indicates this and ythe processmay be stopped. If not 'stopped theback pressure .at the inlet blows fiber back in pipe 4.6. Thus. liber fed into the inlet will valso be blown out the inlet. rThe appearance of back-feed or 'back-pressure is an vindication of the final .status .olf being lled.

Many factors influence the result, and praetically, it is necessary .to ,arrive at standar-d conditions for the particular .equipment used, and the job at hand. For example, it has been found to be a general rule,. tha t the faster the ,fiber is fed, the `less the density of the mat obtained. However, this rule is limited to a very short period Vof time. In one test instance, the feeding time for the space wasvaried `from fractions of a minute to .several minutes. The curve o f density has been plotted vertically against feeding time plotted horizontally. rIhe curve rises rapidly, and at about 25 seconds it begins to hatten out. In about 60 seconds it has reached amaximum density. Such curves were obtained with different fan speeds, and it was foundrthat high speeds '(greater kinetic energy to fiber) at `the same feeding time gave higher density mats. By constructing such curves from experimental'proce dure, the conditions for most efficient operation and for uniform operation,.ma y be easily deter- Y mined.

In opera-tion ofthe arrangements described; with filtering area available at either or both of the openings for the refrigerating unit, the space is quickly filled, with exhaustion of air taking place at allthe Afiltering areas. First, the Vicinity of the screened unit opening fills by filtration, and the mass grows radially therefrom to the top xture (of Fig. 2) where the major part of the air filters through the screens 24.

The use of a fan is preferred for the reason that it is a means of unfelting the fibers to substantially individual fibers. It is this form which gives the best results. However, broadly, Vthe fibers need not be completely unfelted', and may be in clusters .orsmall aggregates. Ilse .of other means, such as vacuum on the screen end, or feeding ber directly into a current of air, is cone ducive to providing such loose aggregates rather than individual particles of fiber. 'Ihe important point is that these `are not under mechanical pressure to felt them, and they -tend to unfelt in process.

The terms screening means and filtering area as used herein or in the claims refer to .an area with any effective lattice or perforated member which acts as a screen to filter particles from l oran/elongated s-lo't.

-It is not vessential that filtering area be limited to -tl1eV unit-openings and the :fixture described, and it may be located-anywhere in the total area confining the space to -be insulated. This-is ex- -empliiiedby the screenedropening I9 in Fig, l. The ysize and location vof filtering Iarea relative' to inlet `area, and the velocityof the stream of gas,

are all such that particles are introduced `withV turbulence -in all vportions of the space Ato -loe insulated, and pack therein.

' Numerous modifications and 'variations Aof the invention, not necessarily related to refrigerators, are contemplated as 'falling Within he Yscope of the appended claims.

Iclaim:

vl. Indepositlng-particles of insulating material into the spacedenedand confined lby walls in.- cluding the Walls of a refrigerator cabinet vand of -a food compartment mounted therein, and inleluding removable closure means over said `space at the door opening .of the refrigerator, said `closure means having a .plurality -of ,introductory inlets .opening finto said .space includi-ng. one Lto each panel-form space at thedoor opening., `.of which walls the spacevconiningisurfaces. include e. 4`manier portion which :is substantially resistant to thepassage .of gas and one `or more remaining portions, each in the form .of screening means with fora/mina relatively minute :compared with said one or more inlets, forv ventinglgas .fromsaid lspaceand 4for retaining said particles in :the spacei of winch-screening means one `lslocated in Aone. of the hack wallsof said refrigerator, the :method which comprises7V suspending in `a moving gas, particles ofinsulating material'which'pack to av consolidated body that is a gas-filtering lood-y at an insulating .densi-ty of therispacked particles; :ln-tro@luci-ng the resulting moving gaseous suspension into said space by. conducting lthe suspension to and through said introductory inlets; simultaneously venting said gas from said space throughsaid screening means, and .there filtering said vented gas from particles, thereby depositing and packing particles to form a growling-gas'filteri-ng mass thereof in corresponding portions of said space .over .and extending away 'from said screening :nieans; simultaneously main'- taining inthe remaining portion .of said space .a condition of turbulence .of saidgaseousfpartclesuspension by maintain-ing a high and sufcient velocity/therefor in introducingv .said suspension whereby the turbulence causes .depesition :and packing o@ .particles in margins of .the turbulent space; continuing said :introduction,V said `main.- tenance of turbulence, and said vventing ofsaid gas through .said screening means `and valso through said growing ima-ss .at least Vunt-il a body of said particles begins to 'form in .each of said inlets and said space is vcompletely. .packed with said particles consolidated to `a gaspfiltering .body aten insulating density and resultinglymolded into said space andpcompressed thereinY by the .differential lintroduction 'pressure between said inlets Vand said Vscreening means.; removing said closure means andretaining 'in'stu the material packed into said space; and applying .a :confining Amaterial over the vopen space left 4by removal of said closure means. y

2. In depositing particles of insulating material into the Vspace defined andeonned by Vwalls including the walls of. a .refrigerator cabinet and of' a foodcompartnient mounted `Vtherein,A and in# Y 9 cluding removable closure means over said space at the door opening of the refrigerator, said closure means having a plurality of introductory inlets opening into said space, of which wallsthe space-confining surfaces include a major portion which is substantially resistant to the passage of gas and one or more remainingportions, `each in the form of screening means with foramina relatively minute compared with said one or more inlets, for venting gas from said spaceandifor retaining said particles in the space,` of which screening means at least one is in said closure, and another is in one of the back walls of the refrigerator, the 'method which comprises, suspending in a moving gas, particles of insulating material which pack to a consolidated body that is a. gas-ltering body at an insulating density of the so-packed particles; introducing the resulting moving gaseous suspension into said space by conducting the suspension to and through said introductory inlets; simultaneously venting said l gas from said space through said screening means, and there ltering said Vented gas from particles, thereby depositing and packing particles to form a growing gas-filtering mass thereof in corresponding portions of said space over and extending away from said screening means; simultaneously maintaining in the remaining portion of said space a condition of turbulence of said gaseous particle-suspension by maintaining a high and sumcient velocity therefor in introducing said suspension whereby the turbulence causes deposition and packing of particles in margins of the turbulent space; continuing said introduction, said maintenance of turbulence, and said venting of said gas through said screening means and also through said growing mass at least until a body of said particles begins to form in each of said inlets and said space is completely packed with said particles consolidated to a gas-ltering body at an insulating density and resultingly molded into said space and compressed therein by the di'erential introduction pressure between said inlets and said screening means; removing said closure means and retaining in situ the material packed into said space; and applying a confining material over the open space left by removal of said closure means,

3. In depositing particles cf insulating material into the space defined and confined by walls including the walls of a refrigerator cabinet and of a food compartment mounted therein, and including removable closure means over said space at the door opening of the refrigerator, said closure means having a plurality of introductory inlets opening into said space including one to each panel-form space at the door opening, of which walls the space-conning surfaces include a major portion which is lsubstantially resistant to the passage of gas and one or more remaining portions, each in the form of screening means with forarnina relatively minute compared with said one or more inlets, for venting gas from said space and for retaining said particles in the space, of which screening means there are at least one in said closure means for each panel space at the door opening, and another in one of the back Walls of the refrigerator, the method which comprises, suspending in a moving gas, particles of insulating material which pack to a consolidated body that is a gas-filtering body at an insulating density of the so-packed particles; introducing the resulting moving gaseous suspension into said space by conducting the suspension to and through said introductory inlets; simultaneously `therefor in introducing said suspension whereby the turbulence causes deposition and packing of particles in margins of the turbulent space; continuing said introduction, said maintenance of turbulence, and said venting of said gas through said screening means and also through said growing mass at least until Va body of said particles begins to form in each of said inlets and said space is completely packed with said :particles consolidated to a gas-filtering body at an insulating density and resultingly molded into said space and compressed therein by the differential introduction pressure between said inlets and said screening means; removing said closure means and retaining in situ the material packed into said space; and applying a confining material over the open space left by removal of said closure means.V

4. In depositing particles of insulating material into the space deiined and confined by walls including the rectangular walls of a refrigerator cabinet and of a rectangular food compartment mounted therein and including a removable closure over a rectangular space peripheral to the food compartment at the door opening of the refrigerator, said lclosure having four spaced introductory inlets opening into said periperal space, of which walls the space-confining surfaces include a major Aportion which is substantially resistant to the passage of gas and one or more remaining portions, each in the form of screening means with foramina relatively minute compared with said four inlets, for venting gas from said space and for retaining said particles in the space, including screening means in said closure and screening means in one of the 'back walls of said refrigerator, the method which comprises, suspending in a moving gas, particles of insulating material which pack to a consolidated body that is a gas-filtering body at an insulating density of the so-packed particles; introducing the resulting moving gaseous suspension into said space by conducting the suspension to and through said introductory inlets; simultaneously venting said gas from said space through said screening means, and there filtering said vented gas from particles, thereby depositing and packing particles to form a growing gasfltering mass thereof in corresponding portions of said space over and extending away from said screening means; simultaneously maintaining in the remaining portion of said space a condition of turbulence of said gaseous particle-suspension by maintaining a high and sufficient velocity therefor in introducing said suspension whereby the turbulence causes deposition and packing of particles in margins of the turbulent space continuing said introduction, said maintenance of turbulence, and said venting of said gas through said screening means and also through said growing mass at least until a body of said"partic1es begins to form in each of said inlets and said space is completely packed with said particles consolidated to a gas-filtering bodyat an insulating density and resultingly molded into said space 11 I2 and compressed thereinv` by diierential intre- UNTED STATES PATENTS ductmn pressure` between said inlets Vand sald screening means; removing Said closure means N11-mbe!" e Name Y Date and retaining in situthemateriaLpaekedintasad 336,231 BaSSeI July 17 1338 space;V andy applying a.` confining ,material over 5 1,180,312 WDI API'- 25, 1916 the peripheral space left byremdvai of said clo- 1,756,463 MOHGI f ADI- 29, 1930 Sure means, v 1,827,853 Tannefy OCt, 20, 1931 CLARK c, HERITAGE 1,923,195 Finck 1 Aug. 22,1933 Q Y 1,971,123 Tappen Aug. 21,1934 REFERENCESl CITED 10 2,170,469 Carter Allg. 22, 1939 lThe following references; are: ofl record in the '2200713 ,Ericson et alf May 14%1946 le of this patenti 

